If it turns out that the problem is an error reading from the hard drive, here's what I would suggest you do. Before you're ready to shutdown for the night, do a Properties on the C: drive (I'm assuming it's the C: drive), select the Tools tab, and under the Error Checking section, click the "Check now" button. Check both check boxes and press the "Start" button. A message will tell you that the scan will start the next time you start Windows. Restart the computer and Windows will run it's scan. It's likely to take several hours, depending upon the size of your drive, which is why I suggested that you let it run overnight, as you won't be able to use the computer while it's scanning. With any luck, the bad sector will either be repaired or marked as bad and the data moved to a "spare" sector. In either case, it should prevent the error from appearing again (at least for that particular sector). You might also want to check the SMART attributes and see if it detects a problem with the drive. If it does, you should backup the drive immediately (you should be doing this on a regular basis anyway) and buy a replacement drive.